[LOGCXX-317] Log4cxx triggers locking inversion, which can result in a deadlock

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.10.0
• Environment: Operating System: Windows 2003 R2; Compiler: Visual Studio 2005 SP1; log4cxx 0.10.0 was compiled as a DLL.; Note: the reported issue is independent of the above data.
• Assignee: Curt Arnold
• Reporter: Bart Van Assche
• Created: 28/Nov/08 09:12
• Updated: 10/Feb/14 13:53
• Resolved: 10/Feb/14 13:52

Description

Calling log4cxx::configureAndWatch() results in Logger::mutex being locked first, and Hierarchy::mutex being locked nested.

Calling log4cxx::getLogger() results in Hierarchy::mutex being locked first, and Logger::mutex being locked nested.

See also the attachment for the full call stacks.

Such behavior is called locking inversion and can result in a sporadic deadlock.

This issue has been found via Intel Thread Checker.
Note: there are also other tools that can detect locking inversion, e.g. the Helgrind tool included with the Valgrind suite.

Issue Links

• is duplicated by: LOGCXX-359 Lock order violation